Oligosaccharides in vertebrate development

The outer surfaces of eukaryotic cells are covered with a dense and complex array of sugar chains (oligosaccharides). Most are found attached to other macromolecules, yielding glycoconjugates such as glycoproteins and glycolipids. Given their location and structural complexity, it is natural to predict their involvement in cell-cell interactions. Several examples of such interactions have been defined in animal systems. Since the expression of many oligosaccharides is tissue-specific and developmentally regulated, they may also be involved in embryonic development. Genetic evidence in favor of this notion has recently been obtained. This article provides a perspective on glycosylation in vertebrate development and experimental approaches towards elucidating oligosaccharide function.